2012 Annual Report
1a.Objectives (from AD-416):
To collaborate in the development of a real-time electronic sensor to detect the growth of Aspergillus flavus on corn.
1b.Approach (from AD-416):
ARS will perform microbiological experiments to obtain data on the volatile gases produced by Aspergillus flavus growing on corn in vitro under laboratory conditions. Sensor Development Corporation will utilize this data to develop a chip-based electronic sensor that detects the major volatiles as determined by ARS.
Aspergillus flavus, commonly found on corn, produce aflatoxins (the most potent natural hepatocarcinogens known) and are banned at concentrations of 20 ppb or higher. When conditions are conducive, it readily grows on stored corn and renders it unsafe. This project identified secondary metabolic volatile compounds that are uniquely produced by toxigenic Aspergillus flavus isolates on both sterile and non-sterile cracked corn. The first study identified the volatiles produced under optimal conditions when this fungus is grown alone on sterile corn. The latter research determined the volatile profile of the Aspergillus flavus isolates when grown on non-sterile corn containing naturally-occurring bacteria and fungi that can interact with Aspergillus flavus and affect the metabolism of this fungus. Unique volatile compounds consisted of alcohols, aldehydes, alkanes, terpenes, and a few other chemical families. The number and identity of the specific volatiles were dependent on the toxigenic isolate tested. Our stakeholder used this data to modify a sensor under development and undergoing Beta testing.